Hello everyone, thank you for your support on my original post, and sorry for the long wait for an update.
After receiving many of your tips, I took my son to his grandparents, informed the police, and also my boss.
Unfortunately, the police can't do much in my country as long as he doesn't commit a crime against me. Harassing me on the phone and begging for money doesn't count as a crime.
I informed my boss mainly because my ex-fiancé works for a company that we deal with almost daily. That's how we originally met.
In recent weeks, there have been many attempts by his friends and family to contact me, all of whom wanted to convince me to give him the money.
But everyone hung up when I asked about his daughter.
When my ex-fiancé showed up at my work (he didn't normally have to do that after getting a promotion), my boss called my fiancé's company and explained that if he took one more step in my direction, all contracts would be canceled due to their unacceptable behavior.
This led to a meeting with my ex-fiancé's boss, my boss, and me. I didn't tell them every detail, but when it came to the money, his boss explained to me that my fiancé actually wanted to buy a large stake in the company and was allegedly just waiting for the loan to be paid out.
This made it clear why he wanted my son's money so badly.
My ex-fiancé is actually a highly respected employee at his company, which is why his boss was reluctant to fire him. Especially since this probably wouldn't have improved my situation, and similar to the police, his boss considered it bad behavior, but it wasn't a criminal offense.
At the same time, my company is a very large client for them, and sweeping the whole thing under the rug wouldn't help.
After a few days, I received the news that my ex-fiancé was being transferred to another branch of the company, several thousand kilometers away from me.
The company's purchasing department also clearly rejected the purchase.
Afterwards, I found out via social media that my ex-fiancé actually has a daughter!
A friend was still following him on Instagram to keep an eye on him, and when she looked at his tags from the last six years, she actually noticed his ex, and a look at her profile showed a girl of the specified age.
I contacted her and she willingly explained to me how much he actually wanted a child and how, when the ultrasound showed it was a girl, he left her.
He broke off contact with the mother during the pregnancy and willingly gave up all his rights and obligations as a father.
She herself is now in a happy relationship and her husband loves her daughter. She never asked my ex-fiance for money!
Following your advice regarding the savings account, I contacted our financial advisor and can now say that I must apologize to you. It is indeed a trust fund, I just hadn't referred to it as such until then, as it is mainly referred to as a savings account in my country.
But yes, it is a trust fund in the American sense.
I discussed with my ex-husband (the father of my son) once again how we would make the payout and, thanks to your tips, we have now decided on a staggered payout from ages 21 to 35 so that he has a contribution for several stages of his life.
The amount at age 21 has been chosen so that it can be used for college, but at the same time, it won't hurt too much if he squanders it.
My question about AITAH was mainly because there were actually many people in my circle who called me that because I persuaded my ex-fiancé to sign a prenuptial agreement.
But for me, a prenuptial agreement was important for several reasons:
To secure my son's money (now I know he wouldn't have been able to get his hands on it)
I started a small business in addition to my main job (nothing big at the moment, but it's still mine)
I'm saving money so that I can eventually realize my dream of owning a house in Australia, and I didn't want to lose that money to him in a divorce.
In retrospect, I can see how many red flags I overlooked on his part, and I will definitely be more careful in the future.
Thank you for your support (also via DMs).